Dear Friends,

I apologize again for the length of this post, but it is in the form of a magazine type article. I hope it informs. Please note that some of the loads reported in this piece I considered too hot. Those that are the direct subject of the piece are +P loadings. In handloading, one should always start low and work up, which is how I got to my starting points. Ku-dude

A little over three years ago, I had Walt Sherman build me a 9.3x62 rifle on a Mark X action. It has a 23 inch, Montana Rifle Works barrel, and a synthetic stock. I specified that it should have iron sights and a barrel band sling swivel because a potential dangerous game rifle needs iron sights, and a barrel band keeps the barrel below your head when carried barrel up and out of the ground carried barrel down.

Walt developed the original loads for it using H4895 and 286grain Nosler Partitions. From the outset, it has been a marvelously accurate rifle. It will routinely shoot groups to a MOA with almost any weight bullet. When clean, it has shot 250BT's to a half minute of angle at 300 yards. It won't necessarily do this with every group, but that may not be the rifle's fault! It will do it with sufficient frequency that it is my hands-down choice for my most accurate rifle, and I have a 30-338 and a 30-06 that are very accurate. However, from the beginning there was one problem with my 9.3: the lack of reliable loading data for this cartridge in modern rifles.

In our litigious society, the folks who make loading manuals do not want to put data out that might be used for older rifles that are not up to modern pressures. This is particularly true when you get into cartridges that made the transition from black powder to smokeless powder and cartridges like the 9.3x62 that, like the 30-06 and 8mm Mauser, have been with us almost since the inception of the smokeless era.

As you may know, modern brass and modern rifles are capable of routinely handling pressures that exceed the current standards for 30-06 and 8mm Mauser. This also is true for the 9.3x62 when using a Model 98 or similar action made with modern steels and good quality brass. The .270 Winchester, for example, is loaded to 51,000-52,000 copper units of pressure (cup) or 62,000psi. Magnums are loaded to similar pressures; however, the modern rifles that shoot them are essentially the same. Therefore, it is possible to reload older cartridges to higher velocities safely if, repeat if, you limit their use to modern rifles. But how to determine the pressure limits if you don't have a Model 43 Oehler?

I have been shooting my rifle with various powders and bullets for about three years, and have saved all my data in my old RCBS computer program. I used this to make a list of all the loads I had tried by bullet weight, by powder and then charge weight. This list included the primer used, the file name in my ballistic program, and a summary of my notes on the load. I then did a web search to find pressure data tied to velocities that I could compare with my data. I found that pressure information was available for various powder and bullet combinations. I concluded that all the manuals I have and on-line data hold maximum loads for the 9.3x62 to about 48,000cup.

I integrated the information I found with my data and I found that my load for the 286grain Partition was about 6 grains over the maximum. The 250grain BT load of 60 grains of H4895 was about 2 to 3 grains in excess of the 48,000cup limit. While I had never had troubles with either load, it was clear to me I potentially was operating at the edge of the envelope. Also in comparing pressure data with my data, it was apparent that 4320, Varget and RL 15 were achieving velocities at maximum pressures that indicated they might exceed with less pressure the velocities I was getting with H4895. I concluded that the time had come to proof my data and see if there were other powders that might prove as useful as H4895 had been. In doing this, I felt I should start by establishing a baseline for H4895 as an "overload."

Although I do not use the Speer 270grain, semi-spitzer bullet for hunting, I elected to do my baseline testing with this bullet because it cost roughly half the price of the other bullets that I use. It has a bearing surface that is close to that of the 286grain Partition, and exceeds both the weight and bearing surface of the 250grain BT. I felt that I could extrapolate my findings to the 250 and 286 bullets in determining a starting point for further testing with those bullets.

Because a modern action is not going to suffer catastrophic failure within the limits of the powders I intended to stuff into the 9.3x62 case, what I was really looking at was useable case life as an indicator of pressure. I concluded that if I could reload a case eight times without the primer pocket loosening or stretching the case to separation, it was a reasonable load. I took as a starting point 59 grains of H4895 with the 270 Speer, which was 2.5 grains more than a 48,000cup maximum loading.

I transported a dies, presses, primers, powders and all the various accoutrements necessary to reload cases to my range where I set up right next to my shooting point during a time when range use was low. I proceeded to reload and shoot the 270grain Speer 40 times with a charge of 59 grains of H4895 ignited by a Federal 210 match primer. The five pieces of new Lapua brass selected at random made it through the entire test intact, without loose primer pockets, and without case splits or indications of imminent case head separation. They could have been reloaded at least a ninth time.

I then switched my attention to Varget because it appeared to be capable of reaching higher velocities within projected pressure limits. I had five cases that I had used to test the 250BT with 61grains of H4895 which were resized and primed. Although scientifically unsound, I started with these cases because they were available.

I had tested previously a load of 60 grains Varget with the 270grain Speer using a Winchester Large Magnum Rifle (WLMR) primer, but I wanted to use 210 match primers throughout the test. Having determined that the difference between a WLMR primer and a Federal 210 match primer roughly equals a grain of powder, I started my Varget tests at 61 grains with a 210 match primer. This proved accurate and showed no pressure signs; therefore, the load was increased to 62 grains. After three tests with 62 grains, the load was increased to 62.5 grains and the last three tests were with this charge. I unscientifically decided, perhaps because of a really sore shoulder, that this was equal to eight loads of 62.5grains, and ceased my testing.

A total of ten Lapua cases were used to fire 80 loads; five cases with H4895 and five cases with mostly Varget. In both tests, the cases were neck sized and there were no difficulties with chambering or extraction in either test. About half way through, the cases were trimmed. At the end of eight reloadings, the primer pockets were not loose and the cases showed no signs of separation. A 2.5grain "overload" of Varget gave almost 50fps more velocity (2500fps) than H4895 gave with a 2.5-grain overload.

Graphs of the various loads indicated that:

(1) Varget maybe very useful in 250BT loads, able to achieve over 2600fps;

(2) The 286 load is overloaded with H4895, but H4895 maybe the ticket in 250BT with which it is very accurate and fast enough (2586fps);

(3) With regard to 286 loads, slightly slower powders like H414 and 4350 might be more useful.

I will continue my testing; however, I wanted to report this preliminary information because of the continuing absence of good data and as an encouragement to others to start testing bullets and primers in a similar fashion. Together maybe we can develop more loads with which we can feel confident because of the methodology by which they were developed.

Please remember that I had a great deal of experience in reloading for this particular rifle prior to starting these trials; that this is a modern rifle made with modern steels; and that it was put together and originally tested by a very good gunsmith. The loads which were tested through eight firings are like +P loads and you should use caution in using them even in modern guns of good quality. The other loads mentioned are in no way recommended. Many are too hot and are reported only to provide the reader with the "rest of the story." Ku-dude

PS: The more I play with the 9.3x62, the more impressed I am with it. Its case volume, bore diameter, and high ballistic coefficient across a range of bullet weights combine for an incredibly balanced cartridge. All in a standard length action that doesn't cost an arm and a leg. It is today exactly what Herr Bock intended just at 100 years ago when it was introduced. With modern powders and bullets, it truly may be more versatile than the .375 and the 30-06 as the all round champion for the most versatile cartridge. k-d

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Thanks for the good read...from an avid 9.3x62 fan !! and a shooter of speer 270 gr bullets to boot

Alf,

I think that what I said is exactly in agreement with what you said. The immediate critical issue is, as you point out, what happens when there is a case failure, and, as I found out when I fed a 06 round into a 30 magnum, the gas "gets out." There is in rifles made before the mid twenties an issue with set back from rechambering them for magnums or shooting very high intensity loads in them. However, with proper treatment they could probably handle the pressures. The issue in modern rifles is not so much the action, but the brass, which my experiment sought to test. There is an issue of subjecting any action to very high pressures which is thought by some to create the potential at some juncture of failure of the reciever or bolt; however, I doubt that any of these loads approaches those pressures.

I don't believe that Mausers prior to the M98 had the protections against gas coming back into the face that the M98 incorporates; however, I might be mistaken. I don't have a M88, but I do have and shoot a M93 Argie, M95 Brazilian, and M38 Swede. I keep the pressures down in all of these with due respect to the age (even older than I!)

I am not familiar with Glacklin's article. What issue of Handloader is that in? I believe a short search on the web will present loadings for .270 Winchester contained in the data of major powder companies showing pressures in the 60,000psi range. However, I would agree with Glacklin that 55,000psi is a sensible limit for brass, and was the pressure that I was attempting to approach, but stay under. The object is not a 9.3x62 Magnum, but loads that take advantage of modern powders and actions.

Ku-dude

Excellent information Ku-dude, thanks. I'm very interested in seeing the rest of your test data/results.I'm a big fan of the 9.3X62.

Alf,

A postscript: I believe that copper units of pressure (cup) are a difference measurement of pressure than pounds per square inch (psi). The cup being based upon pressure required to crush a copper "disk" that was placed in plunger type device that open directly into not only the chamber but into the case. This was subsequently replaced by devices that measured the pressure per square inch (psi) through a similar hole. While some labs still use the cup set ups, I am given to believe that the more modern set ups use electronic strain gauges. I think that "cup psi" mixes the two concepts. Ku-dude

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The 9,3X66 was introduced by Sako 1-2 yrs ago, and is not based on any existing cartridge. Sako wanted to create a cartridge that filled out a standard length action completely and managed to get .375 H&H performance out of their effort. It is not belted. The gain is not large as compared to 9,3x62 though. Here in Sweden 9,3x62 is very much a standard cartridge and is increasing a lot in popularity as wild boar is becoming more and more common. Thus, brass and ammo is very easy to come by/cheap. This isn't exactly the case for the new 9,3x66... Check out Sako's home page for info on the cartridge. Used to be there at least...
The 9,3x74(R) does not (isn't supposed to...) produce any velocity increase as compared to 9,3x62. This cartridge was developed to produce 9,3x62 performance with lower pressures; somthing very much to be desired in the break open doubles and combination guns where it is used.